# YOLOv5 🚀 by Ultralytics, GPL-3.0 license
"""
Download utils
"""

import logging
import os
import subprocess
import urllib
from pathlib import Path

import requests
import torch


def is_url(url, check=True):
    # Check if string is URL and check if URL exists
    try:
        url = str(url)
        result = urllib.parse.urlparse(url)
        assert all([result.scheme, result.netloc])  # check if is url
        return (
            (urllib.request.urlopen(url).getcode() == 200) if check else True
        )  # check if exists online
    except (AssertionError, urllib.request.HTTPError):
        return False


def gsutil_getsize(url=""):
    # gs://bucket/file size https://cloud.google.com/storage/docs/gsutil/commands/du
    s = subprocess.check_output(f"gsutil du {url}", shell=True).decode("utf-8")
    return eval(s.split(" ")[0]) if len(s) else 0  # bytes


def url_getsize(url="https://ultralytics.com/images/bus.jpg"):
    # Return downloadable file size in bytes
    response = requests.head(url, allow_redirects=True)
    return int(response.headers.get("content-length", -1))


def safe_download(file, url, url2=None, min_bytes=1e0, error_msg=""):
    # Attempts to download file from url or url2, checks and removes incomplete downloads < min_bytes
    from utils.general import LOGGER

    file = Path(file)
    assert_msg = f"Downloaded file '{file}' does not exist or size is < min_bytes={min_bytes}"
    try:  # url1
        LOGGER.info(f"Downloading {url} to {file}...")
        torch.hub.download_url_to_file(
            url, str(file), progress=LOGGER.level <= logging.INFO
        )
        assert (
            file.exists() and file.stat().st_size > min_bytes
        ), assert_msg  # check
    except Exception as e:  # url2
        if file.exists():
            file.unlink()  # remove partial downloads
        LOGGER.info(f"ERROR: {e}\nRe-attempting {url2 or url} to {file}...")
        os.system(
            f"curl -# -L '{url2 or url}' -o '{file}' --retry 3 -C -"
        )  # curl download, retry and resume on fail
    finally:
        if not file.exists() or file.stat().st_size < min_bytes:  # check
            if file.exists():
                file.unlink()  # remove partial downloads
            LOGGER.info(f"ERROR: {assert_msg}\n{error_msg}")
        LOGGER.info("")


def attempt_download(file, repo="ultralytics/yolov5", release="v7.0"):
    # Attempt file download from GitHub release assets if not found locally. release = 'latest', 'v7.0', etc.
    from utils.general import LOGGER

    def github_assets(repository, version="latest"):
        # Return GitHub repo tag (i.e. 'v7.0') and assets (i.e. ['yolov5s.pt', 'yolov5m.pt', ...])
        if version != "latest":
            version = f"tags/{version}"  # i.e. tags/v7.0
        response = requests.get(
            f"https://api.github.com/repos/{repository}/releases/{version}"
        ).json()  # github api
        return response["tag_name"], [
            x["name"] for x in response["assets"]
        ]  # tag, assets

    file = Path(str(file).strip().replace("'", ""))
    if not file.exists():
        # URL specified
        name = Path(
            urllib.parse.unquote(str(file))
        ).name  # decode '%2F' to '/' etc.
        if str(file).startswith(("http:/", "https:/")):  # download
            url = str(file).replace(":/", "://")  # Pathlib turns :// -> :/
            file = name.split("?")[
                0
            ]  # parse authentication https://url.com/file.txt?auth...
            if Path(file).is_file():
                LOGGER.info(
                    f"Found {url} locally at {file}"
                )  # file already exists
            else:
                safe_download(file=file, url=url, min_bytes=1e5)
            return file

        # GitHub assets
        assets = [
            f"yolov5{size}{suffix}.pt"
            for size in "nsmlx"
            for suffix in ("", "6", "-cls", "-seg")
        ]  # default
        try:
            tag, assets = github_assets(repo, release)
        except Exception:
            try:
                tag, assets = github_assets(repo)  # latest release
            except Exception:
                try:
                    tag = (
                        subprocess.check_output(
                            "git tag", shell=True, stderr=subprocess.STDOUT
                        )
                        .decode()
                        .split()[-1]
                    )
                except Exception:
                    tag = release

        file.parent.mkdir(
            parents=True, exist_ok=True
        )  # make parent dir (if required)
        if name in assets:
            url3 = "https://drive.google.com/drive/folders/1EFQTEUeXWSFww0luse2jB9M1QNZQGwNl"  # backup gdrive mirror
            safe_download(
                file,
                url=f"https://github.com/{repo}/releases/download/{tag}/{name}",
                min_bytes=1e5,
                error_msg=f"{file} missing, try downloading from https://github.com/{repo}/releases/{tag} or {url3}",
            )

    return str(file)